1. Field of the Invention
This invention relates generally to a method for manufacturing an inner door panel of a vehicle side door and, more particularly, to a method for manufacturing an inner door panel of a vehicle side door that includes die casting the inner door panel with an impact beam as a single integrated cast.
2. Discussion of the Related Art
Much engineering goes in to the design and manufacture of vehicle doors. A typical vehicle side door will include an outer door panel often formed of stamped steel, an inner door panel also formed of stamped steel and a trim panel. An impact beam is typically bolted or welded to the inner door panel so that it is between the inner door panel and the outer door panel for providing protection against side impact. Also, various reinforcement members are often welded to the inner door panel, such as a latch reinforcement member, a hinge reinforcement member and a waist reinforcement member. Once the reinforcement members and the impact beam are mounted to the inner door panel, the outer door panel is then secured to the inner door panel by folding over and joining an edge of the outer door panel to the inner door panel in a hemming process to provide a door in white. The inner trim panel is then mounted to the inside surface of the inner door panel. The various door hardware, such as window switches, motors, latch mechanisms, wiring, etc., are assembled at the appropriate time during the assembly process. Although the inner door panel, the outer door panel, the impact beam and the reinforcement members are typically made of steel, some or all of these components have been known to be made from other materials such as aluminum and polymers.
Die casting is a known metal forming process where a molten metal in a liquid state, such as aluminum or magnesium alloys, is poured or otherwise caused to flow within a die cavity defined by opposing die halves and cooled to be solidified therein to form the particular component. During the casting process, the die halves are clamped together and the molten metal is caused to flow through an orifice into the die under high pressure via a plunger through a shot-sleeve. Once the molten metal has solidified, the die is opened and the now hardened part is removed.
Die casting offers a number of advantages over stamping, forging and other metal forming processes including the ability to form highly complex or intricate part, simplified design and manufacturing and assembly processes, better quality, higher productivity due to a near net-shape process, etc. However, in order to allow a particular part to be die cast, it is necessary that the configuration of the part be such that all areas of the die cavity be filled with molten metal to form the part and allow the die halves to be separated without interference from the part.